Heat transfer from the stator end-windings of a low voltage concentric-wound induction motor

Heat transfer coefficients on the end-windings of a through-ventilated concentric wound induction motor are presented together with details of the air flow distribution and flow patterns in the end regions. The overall heat transfer coefficients derived from the power input differ from those measured locally using heat flux gauges. The differences are attributed to the much larger actual surface area exposed to the flow than the area of the outer envelope of the end-windings on which the calculation of the overall heat transfer coefficients has been based. The values obtained differ also from those for a lap wound motor reported earlier. This difference is attributed to the difference between the real and envelope areas of the end-windings in the two machines and to changes in the air flow pattern in the end region at the air inlet end.